Die apparatus for cutting end of bumper bar

ABSTRACT

A die apparatus includes a first die configured to telescopingly engage an end section of a tubular bar, including one or more “floating” mandrels configured to extend into cavities of the tubular bar, and further including a stationary die member spaced from the mandrel(s). The mandrel(s) and the stationary die member include angled cutting edges that are aligned so that the cutting edges are engageable from a single transverse direction. The mandrel(s) is movably supported on the first die to float parallel the single direction toward and away from the stationary die member. A cutting die has a shearing punch configured to move along the single direction to sequentially engage the angled cutting edges to shear off an angled portion of the end section. The die apparatus is optimally designed for use with a rollformed swept tubular bumper bar having a B-shape and that has walls forming first and second tubular sections that define first and second cavities, with the walls further defining a third cavity between the first and second cavities. In such a die apparatus, the first die includes first, second, and third mandrels configured to extend into the first, second, and third cavities, respectively, of the B-bumper. A method related to the above apparatus is also disclosed.

[0001] This application is a divisional of U.S. application Ser. No.09/081,376, filed on May 19, 1998, entitled DIE APPARATUS FOR CUTTINGEND OF BUMPER BAR, now U.S. Pat. No. ______.

BACKGROUND OF THE INVENTION

[0002] The present apparatus relates to a die apparatus for cuttingangles onto end sections of a vehicle bumper bar made from high strengthsteel, where the bumper bar has tubular sections extendinglongitudinally along its length.

[0003] Recently, novel rollforming apparatuses and methods were patentedfor forming high strength swept tubular vehicle bumpers. For example,see U.S. Pat. Nos. 5,092,512; 5,104,026; 5,395,036; and 5,454,504.Bumpers made by these apparatuses and methods typically have theadvantage of a lower weight and greater strength-to-weight ratio thanconventionally stamped bumper bars, and further their manufacturing costis typically lower or at least very competitive with processes forstamping conventional bumpers for high volume runs. These bumper barshave a continuous curvilinear sweep well-suited for vehicles having anaerodynamic appearance, such as vehicles having rounded front corners.

[0004] However, vehicle manufacturers have recently designed bumper barswith a compound angle along a front face of the bumper bar at its ends.The compound angle provides an increased sweep at the vehicle fenders,giving a visual effect that is even more aerodynamic in appearance. Therollforming apparatuses and methods disclosed in the above-noted patentsare adapted to manufacture a continuous tubular bumper section, whichcontinuous tubular bumper section may have pre-pierced or pre-punchedholes, but the rollforming apparatuses and methods are not adapted tomake a tubular bumper section having a compound angle on ends of thebumper sections. This presents a problem since the ultra-high strengthmaterial used to make the rollformed swept tubular bumpers is not easilydeformed or cut once the tubular bumper section is formed, in partbecause it is difficult to support an inside of a tube section after thebumper is formed. As a result, secondary operations intended to form acompound angle on ends of the tubular bumper sections typically areexpensive, have slow cycle times, are maintenance problems, and/or aredifficult quality control problems. In addition, it is noted that thecorners of a vehicle must pass stringent federal regulations, includingcorner impact strengths for bumpers, as well as pass stringent qualitycontrol standards, such that the reliability of any process used to makethe compound angle must be very good and repeatable. Also, the frontcorners of vehicles are highly visible and subject to consumer scrutiny,such that any process used to make the compound angle must be capable ofbeing dimensionally accurate and must be capable of being held to tighttolerances. At the same time, the automotive industry is verycompetitive, such that the cost of secondary operations to put acompound angle into a bumper section must be minimized.

[0005] One secondary operation presently used to form a compound angleat an end of a tubular bumper beam includes using carbide-tippedcoldsaws to cut away a pie-shaped section, and then welding a plate ontothe cut-away area to form the compound angle. A problem is that thecoldsaw blades quickly wear out, or bind and break, or wander(particularly as they enter the bumper section at an angle) such thatthey do not provide an accurate or quick cut. Each of these problemscause downtime and/or expense. Further, the process of cutting a bumperwith a coldsaw takes up an unacceptably long time, and can result inunacceptable burrs. Consequently, the process of cutting a tubularbumper made of high strength steel material with a coldsaw results inslow cycle times, broken and worn-out blades requiring constantmaintenance, and higher than desired cost.

[0006] Another secondary operation presently used to form a compoundangle is to slit or cut top and bottom walls of the tubular bumpersection, compress the front face of the tubular bumper section towardits rear face to form the compound angle, and then weld the top andbottom walls together to permanently secure the front and rear faces inthe position forming the compound angle. However, this method sometimesdoes not accurately form the compound angle. Further, it is difficult toslit or cut intermediate walls that are located between outer top andbottom walls, such as when there are multiple tubes formed in thetubular bumper section. For example, a “B” shaped bumper is an exampleof a bumper section having multiple tubes formed therein, includingintermediate walls. (See U.S. Pat. No. 5,395,036.) A coldsaw can beused, but then there are the problems noted above with high maintenance,slow cycle times, and quality problems.

[0007] Still another secondary operation presently used is to weld anend bracket onto the ends of a “short” tubular bumper section, with theend bracket completely forming an end of the bumper section, includingtop, bottom, and side walls. However, this design requires carefulquality control of the welding process to assure that the welds aresufficient to meet federal regulations on corner bumper impact tests,keeping in mind that in this bumper design, the welds must takesubstantial loads on impact. It is noted that the ultra-high strengthmaterials of the present bumper sections can be difficult to reliablyweld on, due partially to the strength of the material, and the thinnessof the sheet stock used. Further, the dimensions of the end bracket andits assembly onto the bumper section can be difficult to controldimensionally.

[0008] Another secondary operation uses dies to mechanically crush endsof the tubular bumper section, with the front and rear walls on ends ofthe tubular bumper section being forced together to form the compoundangle and with the top and bottom walls being crushed to allow the frontand rear walls to come together. (For example, see U.S. Pat. No.5,306,058, although it is noted that the bumper in U.S. Pat. No.5,306,058 has the crushed surface on its back side and not on its frontside.) However, it is difficult to control the dimensions of crushedends, and further, it is difficult to deform the high strength steelmaterial used to make the tubular bumper sections, particularly afterthe tubular bumper section is formed. This is particularly true forB-shaped tubular bumper sections, where there are intermediate wallsthat extend perpendicularly to the direction of the crushing forces andthat resist the crushing process. Notably, these intermediate walls aredifficult to access to pre-notch or to engage to control theirdeflection during the deformation process.

[0009] Up until the present invention, die apparatuses and relatedmethods were generally considered to be poor alternatives to cut apie-shaped section off of a side and end of a tubular bumper to form acompound angle thereon for several reasons. In order to use shearingdies for cutting off a pie-shaped section, the tube section of the highstrength material being cut would have to be supported on the inside andthe outside of the tube section for several inches into an end of thetube section. Further, the “inside” support would have to besufficiently strong to not break during the die cutting process and bestrong enough not to have trouble maintaining the position of itscutting edge, yet it would have to be small enough to fit inside thetubular concavity of the tubular bumper. These problems are aggravatedby the ultra-high strength material of the bumper, the very thin wallsections of the bumper materials, and the existence of multiple tubesections in some tubular bumper bars, which tube sections do not alwayshave consistent dimensions as they come off the rollforming apparatusthat forms the tubular bumper. Further, it is noted that shearing diesfor cutting off material have cutting edges that have critical clearancedimensions that must be tightly held.

[0010] Accordingly, an improved process solving the aforementionedproblems and having the aforementioned advantages is desired.

SUMMARY OF THE PRESENT INVENTION

[0011] In one aspect of the present invention, a die apparatus isprovided that is adapted to engage and cut an end of a tubular bar madefrom high strength sheet steel, the tubular bar having walls formingfirst and second tubular sections that define first and second cavitieswith the walls further defining a third cavity between the first andsecond cavities. The die apparatus includes a first die configured totelescopingly engage an end section of the tubular bar, including first,second, and third mandrels configured to extend into the first, second,and third cavities, respectively, and including cutting edges that arealigned so that the cutting edges are engageable from a single directionthat extends transversely to the first, second, and third mandrels. Acutting die has a shearing punch configured to move along the singledirection to pass operably across the aligned cutting edges tosequentially shear the walls to remove a portion of the end section.

[0012] In another aspect, a die apparatus includes a first dieconfigured to telescopingly engage an end section of the tubular bar,including a first mandrel configured to extend into at least one cavityof the tubular bar, and further including a stationary die member spacedfrom the first mandrel. The first mandrel and the stationary die memberinclude angled cutting edges that are aligned, so that the cutting edgesare engageable from a single direction. The first mandrel is movablysupported on the first die to float parallel the single direction towardand away from the stationary die member. A cutting die has a shearingpunch configured to move along the single direction to sequentiallyengage the angled cutting edges to shear off an angled portion of theend section.

[0013] In yet another aspect of the present invention, a method formanufacturing vehicle bumpers made of high strength steel includesproviding a tubular bar having walls forming at least one tubularsection defining at least one cavity, and providing a die apparatusincluding a first die configured to telescopingly engage an end sectionof the tubular bar, the first die including a first mandrel configuredto extend into the cavity in the tubular bar, and further including astationary die member spaced from the first mandrel. The first mandreland the stationary die member include angled cutting edges that arealigned so that the cutting edges are engageable from a singledirection, and the first mandrel is movably supported on the first dieto float parallel the single direction toward and away from thestationary die member. The die apparatus further includes a cutting diehaving a shearing punch configured to move along the single direction tosequentially engage the angled cutting edges to shear off an angledportion of the end section. The method includes extending the endsection of the tubular bar into engagement with the die apparatus, andoperating the die apparatus by moving the shearing punch to shear offthe angled portion of the end section.

[0014] These and other features, advantages, and objects of the presentinvention will be further understood and appreciated by those skilled inthe art by reference to the following specification, claims, andappended drawings.

DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a top view of a tubular bumper;

[0016]FIG. 1A is a cross-sectional view taken along line IA-IA in FIG.1;

[0017]FIG. 2 is a perspective view of an end section of the tubular barshown in FIG. 1, with a pie-shaped section of scrap shown sheared awayfrom the end section;

[0018]FIG. 3 is a perspective view of the end section of the tubularbumper shown in FIG. 1, including an end plate welded to the endsection;

[0019]FIG. 4 is a perspective view of a die apparatus embodying thepresent invention, the die apparatus being configured to cut thepie-shaped section of scrap from the end section of the tubular barshown in FIG. 2;

[0020]FIG. 5 is a fragmentary top view of FIG. 4;

[0021]FIG. 6 is a perspective view similar to FIG. 4, but showing thetubular bar of FIGS. 1-3 engaged with the die apparatus of FIG. 4;

[0022]FIG. 7 is a perspective view similar to FIG. 6, but showing thetubular bar pulled partially away from the die apparatus of FIG. 4 butin-line and ready to be engaged therewith;

[0023]FIG. 8 is an exploded perspective view showing the tubular barready to be engaged with the mandrels of the present die apparatus; and

[0024]FIG. 9 is a flow chart showing a method of manufacturing a bumperbar using the present die apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0025] For purposes of description herein, the terms “upper”, “lower”,“right”, “left”, “rear”, “front”, “vertical”, “horizontal”, andderivatives thereof shall relate to the invention as oriented in FIG. 4with the “front” being in a direction out of the page. However, it is tobe understood that the invention may assume various alternativeorientations, except where expressly specified to the contrary. It isalso to be understood that the specific devices and processesillustrated in the attached drawings and described in the followingspecification are simply exemplary embodiments of the inventive conceptsdefined in the appended claims. Hence, specific dimensions and otherphysical characteristics relating to the embodiments disclosed hereinare not to be considered as unnecessarily limiting.

[0026] A die apparatus 40 (FIG. 7) includes a lower first die 41configured to telescopingly engage an end section of a tubular bar 10,such as is used for manufacturing a B-shaped vehicle bumper bar 9 (FIGS.1, 3, and 9). The first die 41 (FIG. 8) includes vertically movable“floating” mandrels 42-44 configured to extend into the at least onecavity of the tubular bar 10, and further includes a stationary bottomdie member 45 spaced below the bottom mandrel 44. The mandrels 42-44 andthe stationary die member 45 include upwardly facing angled cuttingedges that are aligned so that the cutting edges are engageable from asingle direction 46. The mandrels 42-44 are movably supported on thefirst die 41 to float parallel the single direction 46 toward and awayfrom the stationary die member 45. A cutting die 47 has a shearing punchconfigured to move downwardly along the single direction 46 tosequentially engage the angled cutting edges to shear off a pie-shapedangled scrap portion 23′ (FIG. 2) of the end section of the tubular bar10. The illustrated die apparatus 40 is optimally designed for use withthe illustrated tubular bar 10 having a B-shape and that has wallsforming first and second tubular sections that define first and secondcavities, with the walls further defining a third cavity between thefirst and second cavities. In particular, the mandrels 42-44 float in amanner allowing the mandrels to adjust relative to each other and to thetubular bar 10 as the bumper section is extended onto the first die 41,thus allowing the die apparatus 40 to function without binding evenwhere the tubular bars 10 are not dimensionally perfectly consistentfrom one bar to the next. However, the scope of the present invention isnot believed to be limited to only use with a B-shaped bumper. Inparticular, it is specifically contemplated that the present inventioncan be used on a single tube bumper. It is also contemplated that one,two, or three of the mandrels can be made to float, while the othersremain fixed.

[0027] The illustrated tubular bar 10 comprises a B-shaped componentthat is used in manufacturing a vehicle bumper bar 9 (see FIGS. 1, 1A,2, and 3) made of ultra-high strength sheet steel of 120 KSI tensilestrength or higher, and a sheet thickness of about 0.072 inches or less.The sheet steel is rollformed into a swept tubular bumper shape withapparatuses and processes as shown in U.S. Pat. Nos. 5,395,036 and5,454,504, which patents were previously mentioned in the background.The tubular bar 10 (FIG. 1A) includes a center flange 11 and a pair oftube sections formed by intermediate walls 12, rear walls 13, outerwalls 14, and front walls 15. The edges 16 of walls 15 are welded tocenter flange 11, such as at weld 17. Weld 17 can also be spaced awayslightly from the abutting ends of edges 16. Holes 18 and 19 (FIG. 8)are pre-pierced in the end sections 20 on walls 15 at a predetermineddistance from an end of the bumper, and a hole 21 is pierced betweenholes 18 and 19 to remove a section of the weld 17. The cross section ofthe bumper 10 forms two rectangular tubular cavities 24 and 25 and achannel-like cavity 26 between the two cavities 24 and 25.

[0028] The tubular bar 10 (FIG. 1) includes a continuously swept centersection 27, and end sections 28 and 29 each having a pie-shaped scrappiece 23′ (FIG. 2) therefrom cutoff at an angle relative to the frontface deformed by walls 15. Specifically, a part of the face of the endsections 28 and 29, including a portion of the walls 13-15, is cut offalong line 23 (FIG. 8) from end sections 28 and 29 in order to form agreater angle (i.e., a compound angle) at the ends of the bumper. Thecompound angle is located at the front corners of the vehicle when thetubular bumper bar 10 is mounted on the vehicle. A U-shaped plate 30(FIGS. 1 and 3) is welded onto the ends 28 and 29 along the face, andincludes a front plate 31 that forms the compound angle on the face ofthe tubular bar 10, and side attachment flanges 32 that are welded tothe outer walls 14.

[0029] The die apparatus 40 (FIG. 4) includes a stationary base platen50 and movable top platen 51, and further includes guide posts 52 andbushing 53 to guide closure of the movable die 47 onto the lower fixeddie 41 as the movable platen 51 is brought toward stationary platen 50.First die 41 includes a mounting block 54 attached to base platen 50.The mounting block 54 includes a recess with top and bottom flanges 55,and the mandrels 42-44 each include rear ends 57 that extend into therecess and that are secured to mounting block 54 by pins 58 and 59 (FIG.8). Pins 58 and 59 (FIGS. 5 and 8) extend vertically through the top andbottom flanges 55 and 56, and through the secured ends 57. The mandrels42-44 are each shaped to substantially fill a vertical dimension of therespective cavities 24-26 that they engage, so that the tubular bar 10is not vertically crushed during the die-cutting operation, as discussedbelow. However, the mandrels 42-44 have a horizontal dimension somewhatless than the horizontal dimension of the cavities 24-26 so that themandrels 42-44 can be easily extended into the cavities 24-26 withoutbinding. This also allows the mandrels 42-44 to be extended into thecavities 24-26 at an acute angle, as shown in FIG. 5. The mandrels 42-44are spaced apart by wave washers or the like on pins 58 and 59, so thatthe walls 12 and 14 of tubular bar 10 fit between the mandrels 42-44 andso that the mandrels 42-44 can be moved to compress or decompress thewashers. In particular, the mandrels 42-44 are configured to be extendedinto the cavities 24-26 at a slight angle to the arcuate longitudinalaxis 60 of the tubular bar 10 (FIG. 5), thus maximizing the efficiencyand speed of the die cutting operation by providing maximum clearancefor the insertion. The cutting edges 61 of the mandrels 42-44 alignvertically and face forwardly as shown in FIG. 8, so that the cuttingdie 47 sequentially engages them during downward movement of the cuttingdie 47. The surfaces below the cutting edges 61 are recessed to allowthe cutting die 47 to easily pass by. Stationary bottom die member 45provides a cutting edge that also aligns vertically with the othercutting edges 61.

[0030] Cutting die 47 (FIG. 4) includes a punch or protruding die parthaving a cutting edge 63 (FIG. 8) shaped to matingly, shearingly engagethe cutting edges 61 on mandrels 42-44 and bottom die member 45. Thecutting edge 63 is configured to initially begin its shearing actionagainst the cutting edges 61 at the end of the mandrels 42-44, whichlocation corresponds to the holes 18, 19, and 21 on the tubular beam 10(see FIG. 8). Alternatively, the shearing action may begin anywherealong the cutting edges 61, as determined by engineering considerations.As the punch 62 is extended (i.e., as the movable platen 51 is lowered),the punch 62 sequentially engages the mandrels 42-44 and then engagesthe stationary bottom die member 45 to shear the walls 12 and 14 of thetubular bumper 10, to remove the pie-shaped scrap piece 23′ from theends 28 (and 29) of the tubular bar 10. It should be kept in mind thatthe pie-shaped piece 23′ is considerably distorted and deformed duringthe die cutting process, although FIG. 2 does not show this in order tobe clearer as to the pie-shaped piece being removed.

[0031] Fixturing blocks 66 and 67 (FIG. 4) are attached to stationarybase platen 50, and are spaced apart a distance to accurately guidemovement of end section 30 of the tubular bar 10 onto the mandrels42-44. A concave surface 68 on a third fixturing block 68′ captures theend section 30 as the tubular bar 10 is guided onto the mandrels 42-44,and an abutment surface 69 on the fixturing block 54 engages an end ofthe tubular bar 10 to arcuately stop insertion of the tubular bar 10onto the mandrels 42-44. A pneumatic device 70 includes an extendablerod adapted to engage the tubular bar 10 to help hold the tubular bar 10in place during the die cutting operation. A stabilizer rod 72 isattached to an end of the center mandrel 43. The stabilizer rod 72extends through the outwardly facing open side of the channel cavity 26in the tubular bar 10, when the tubular bar 10 is inserted onto themandrels 42-44. The pneumatic device 70 can also be adapted to providepower to a kick-away assist member for forcibly ejecting the tubular bar10 from the lower first die 41 after the pie-shaped scrap 23′ is removedfrom the tubular bar 10.

[0032] Having described the important features and components of thepresent apparatus, its method of use should now be clear to a person ofordinary skill in this art. As shown in FIG. 9, the tubular bar 9 isformed in a rollforming apparatus that forms its tubular shape, welds itin that shape, sweeps it into a longitudinally curved shape, and thencuts it to length. The rollformed swept tubular bar 10 is then movedinto engagement with the lower first die 51, with the mandrels 42-44 ofthe first die 51 extending into the cavities 24-26 of the tubular bar 10at an acute angle (see FIG. 7 and then FIG. 6). Advantageously, themandrels 42-44 float vertically to facilitate inserting the tubular bar10 fully onto the first die 50, and further the mandrels 42-44 areshaped to have a dimension less that the cavities 24-26 in at least onedirection so that insertion of the tubular bar 10 can be relativelyeasily accomplished. The walls 14 and 15 of the tubular bar 10 engagethe fixturing blocks 66 and 67, including the concave guiding surface 68and abutment surface 69. A clamping rod on the pneumatic device 70engages the tubular bar 10 to hold the tubular bar 10 in position on thedie apparatus 40 as the movable die 47 is brought into operativeengagement with the lower first die 41. In particular, as the movabledie 47 is lowered, its cutting edge 63 sequentially engages the alignedcutting edges 61 of the mandrels 42-44 and bottom die member 45 tocuttingly shear away the pie-shaped scrap section 23′ along line 23. Themovable die 47 is then moved vertically away, and the tubular bar 10 isremoved with a compound angled front surface formed thereon. The anglecutting process is repeated, unless it is unnecessary, such as when theoriginal cutting step at an end of the rollforming process cuts an endof the tubular bar 10 at an angle. Plates 30 are then welded onto theends 28 and 29 of the tubular bar 10 to form the bumper bar 9, alongwith mounting brackets for mounting the bumper bar 9 to a vehicle, andalong with any other accessory or attachment brackets.

[0033] It is contemplated that the die apparatus 40 could be positionedin-line with an end of the rollforming process, such that at least oneend of the tubular bar 10 could be formed in-line with the rollformingprocess as part of a continuing process. For example, the present dieapparatus 40 could be aligned with any of the processes shown in any ofU.S. Pat. Nos. 5,092,512; 5,104,026; 5,395,036; and/or 5,454,504.

[0034] In the foregoing description, it will be readily appreciated bythose skilled in the art that modifications may be made to the inventionwithout departing from the concepts disclosed herein. Such modificationsare to be considered as included in the following claims.

The invention claimed is:
 1. A method for manufacturing vehicle bumpersmade of high strength steel comprising steps of: providing a tubular barhaving walls forming at least one tubular section defining at least onecavity; providing a die apparatus including a first die configured totelescopingly engage an end section of the tubular bar, the first dieincluding a first mandrel configured to extend into the at least onecavity, and further including a stationary die member spaced from thefirst mandrel, the first mandrel and the stationary die member includingangled cutting edges that are aligned so that the cutting edges areengageable from a single direction, and the first mandrel being movablysupported on the first die to float parallel the single direction towardand away from the stationary die member; the die apparatus furtherincluding a cutting die having a shearing punch configured to move alongthe single direction to sequentially engage the angled cutting edges toshear off an angled portion of the end section; extending the endsection of the tubular bar into engagement with the first die with thefirst mandrel engaging the at least one cavity; and operating the dieapparatus by moving the shearing punch to shear off the angled portionof the end section, including allowing the first mandrel to adjustvertically along the single direction.
 2. The method defined in claim 1wherein the step of extending the end section includes moving the firstmandrel along the single direction to accommodate the tubular bar as thetubular bar is extended onto the first mandrel.
 3. The method defined inclaim 1 wherein the first die further includes second and third mandrelsextending parallel and spaced from the first mandrel, and the tubularbar includes walls defining first and second tubes with first and secondcavities and a third cavity located therebetween, and wherein the stepof extending the end section includes extending the first, second, andthird mandrels into the first, second, and third cavities, respectively.4. The method defined in claim 1 including a step of rollforming thetubular bar from ultra-high strength steel having a tensile strength ofat least 120 KSI.
 5. The method defined in claim 4 including a step ofproviding fixturing on the first die for receiving a swept tubular bar,and wherein the step of providing a tubular bar includes providing aswept tubular bar having a longitudinally curved shape.
 6. The methoddefined in claim 1 including a step of welding a plate onto the tubularbar to manufacture a highly stylized vehicle bumper bar having a frontsurface with a compound angle at its ends.
 7. A method for manufacturingvehicle bumpers made of high strength steel comprising steps of:providing a tubular bar having walls forming first and second tubularsections that define first and second cavities, with the walls furtherdefining a third cavity between the first and second cavities; providinga first die having first, second, and third mandrels; providing thefirst, second, and third mandrels with first, second, and third cuttingedges, respectively; aligning the first, second and third cutting edgefor operative engagement from a single direction that extendstransversely to the first, second, and third mandrels; telescopinglyengaging an end section of the tubular bar with the first die; extendingthe first, second, and third mandrels into the first, second, and thirdcavities, respectively; providing a cutting die having a shearing punch;moving the shearing punch of the cutting die along the single directionto pass operatively across the aligned cutting edges; and sequentiallyshearing the walls to remove a portion of the end section.
 8. The methodfor manufacturing vehicle bumpers of claim 7 , wherein: the step ofproviding the first die includes providing fixturing blocks; and furtherincluding the step of guiding the tubular bar onto the first die along alongitudinal direction; wherein the first, second, and third cuttingedges of the first, second, and third mandrels each extend at an angleto the longitudinal direction.
 9. The method for manufacturing vehiclebumpers of claim 8 , further including: orientating the first, second,and third cutting edges; and cutting a pie-shaped section of scrapmaterial off of a side of the end section.
 10. The method formanufacturing vehicle bumpers of claim 9 , further including: receivingand securing the tubular bar with the fixturing blocks; and wherein thetubular bar has a continuous cross-sectional shape and has alongitudinal shape that extends along a curvilinear path.
 11. The methodfor manufacturing vehicle bumpers of claim 8 , further including:mateably receiving the tubular bar with the fixturing blocks, thetubular bar having predetermined height and width dimensions; andproviding the first mandrel with a corresponding height dimension aboutequal to the predetermined height dimension, but a corresponding widthdimension that is substantially reduced from the predetermined widthdimension.
 12. The method for manufacturing vehicle bumpers of claim 11, further including: orientating the first mandrel in the first die tofit at an angle into the first cavity in the tubular bar.
 13. The methodfor manufacturing vehicle bumpers of claim 7 , further including:movably attaching at least one of the first, second, and third mandrelsto the first die for movement generally toward or away from the othermandrels.
 14. The method for manufacturing vehicle bumpers of claim 13 ,further including: attaching the one of the first, second, and thirdmandrels to the first die with a pair of attachment pins that extendalong a direction defined by movement of the one mandrel.
 15. The methodfor manufacturing vehicle bumpers of claim 13 , further including:movably supporting at least the second and third mandrels by the firstdie for movement when positioning the tubular bar on the first die andwhen operating the cutting die.
 16. The method for manufacturing vehiclebumpers of claim 7 , wherein: the step of providing the tubular barincluding making the tubular bar from ultra-high strength sheet steelhaving a tensile strength of at least 120 KSI and a thickness less thanabout 0.072 inches.
 17. The method for manufacturing vehicle bumpers ofclaim 7 , wherein: the first, second, and third mandrels have opposingsides that are relatively flat for engaging opposing surfaces on flatwalls of the tubular sections.
 18. The method for manufacturing vehiclebumpers of claim 17 , wherein: the first, second, and third mandrels aregenerally rectangular, but include recessed surfaces adjacent therespective cutting edges that are relieved for clearance from thecutting die during the step of sequentially shearing the walls.
 19. Amethod of cutting an angle into an end of a tubular bar comprising stepsof: providing a tubular bar made from high strength steel, the tubularbar having walls forming at least one tubular section defining at leastone cavity; providing a first die having a first mandrel and astationary die member spaced from the first mandrel, the first mandreland the stationary die member including angled cutting edges that arealigned so that the cutting edges are engageable from a singledirection; telescopingly engaging an end section of the tubular bar withthe first die; extending the first mandrel into the at least one cavity;movably supporting the first mandrel on the first die to float parallelthe single direction toward and away from the stationary die member;providing a cutting die having a shearing punch; moving the shearingpunch of the cutting die along the single direction; and sequentiallyengaging the angled cutting edges with the shearing punch to shear offan angled portion of the end section.
 20. The method of cutting an angleinto an end of a tubular bar of claim 19 , wherein: the step ofproviding the first die includes providing fixturing blocks defining alongitudinal direction; and further including the step of accuratelyreceiving the tubular bar onto the first die along the longitudinaldirection; wherein the cutting edges of the first mandrel extend atangle to the longitudinal direction defined by the fixturing blocks. 21.The method of cutting an angle into an end of a tubular bar of claim 20, further including: arranging the cutting edges to cut a pie-shapedsection of scrap from the end section of the tubular bar.
 22. The methodof cutting an angle into an end of a tubular bar of claim 21 , wherein:the fixturing blocks are configured to receive a swept tubular barhaving a constant cross section and a non-linear length.
 23. The methodof cutting an angle into an end of a tubular bar of claim 19 , furtherincluding: movably mounting the mandrel on the first die to float duringinsertion of the tubular bar onto the first die.
 24. The method ofcutting an angle into an end of a tubular bar of claim 20 , wherein: thetubular bar has predetermined height and width dimensions; and furtherincluding the step of receiving the tubular bar with the fixturingblocks; wherein the mandrel has a corresponding height dimension aboutequal to the predetermined height dimension, the corresponding heightdimension extending parallel the single direction so that the tubularbar is not adversely deformed during the step of moving the shearingpunch of the cutting die along the single direction, but the mandrel hasa corresponding width dimension substantially less than thepredetermined width dimension so that the tubular bar can be readilypositioned on the mandrel.
 25. The method of cutting an angle into anend of a tubular bar of claim 24 , further including: fitting themandrel into the cavity at an angle.
 26. The method of cutting an angleinto an end of a tubular bar of claim 19 , wherein: the step ofproviding the tubular bar includes making the tubular bar fromultra-high strength sheet steel having a tensile strength of at least120 KSI and a thickness less than about 0.072 inches.
 27. The method ofcutting an angle into an end of a tubular bar of claim 19 , wherein: themandrel has flat opposing sides for engaging flat walls of the tubularbar.
 28. The method of cutting an angle into an end of a tubular bar ofclaim 19 , wherein: the mandrel is generally rectangularly shaped, butincludes a recessed surface adjacent the cutting edge that is relievedfor clearance from the cutting edge when moving the cutting die alongthe single direction past the cutting edge.